SCS is a type of neurostimulation that provides valuable treatment for chronic intractable neuropathic pain, angina pectoris, peripheral vascular disease or other conditions. To this end, an SCS system may be implanted within the body to deliver electrical pulses to nerves along the spinal cord. The SCS system typically includes a generator device similar to a pacemaker but equipped to send electrical pulses to leads mounted along nerves near the spine. The generator is usually implanted in the abdomen or buttock area. The stimulation leads may include thin wires or paddles for delivering electrical pulses to the nerves along the spinal cord. An external controller, similar to a remote control, is provided to allow the patient to control or adjust the neurostimulation.
Currently, prior to permanently implanting an SCS system, the patient undergoes a trial period during which he or she is implanted with a percutaneous lead that is externalized and connected to an external stimulation system. The patient must carry the trial stimulation system with him or her. In United States, patients typically have the trial system for less than a week. In Europe, the trial period can last up to a month. During the trial period, the externalized line can become infected and is very cumbersome for the patient. Therefore, it would be desirable to provide a trial neurostimulation system that is far more comfortable for the patient and substantially impervious to infection, and at least some of the aspects of the invention are directed to these ends.
Note that at least some neurostimulation devices are equipped for both trial operation and subsequent chronic operation. See, for example, U.S. Patent Applications 2006/0190048 and 2006/0195152. With such devices, assuming trial stimulation is successful, the device can be switched from trial mode to chronic mode. If trial stimulation is not successful, the device is explanted. Although such “dual-operation” systems can eliminate the need for a conventional externalized trial system, various issues remain. Since the implantable device must be equipped for full long-term chronic-mode operation (as well as short-term trial operation), it must have all of the components needed for such long-term operation, including a relatively large battery or set of batteries. Accordingly, such dual-operation devices would be at least the same size as chronic neurostimulation devices. There are various burdens and risks associated with initially implanting and subsequently explanting such devices. In particular, if neurostimulation ultimately proves to be unwarranted within a particular patient, that patient must endure the burdens and risks associated with implantation of the full-sized chronic device and then its subsequent explantation.
Accordingly, it would be desirable to instead provide an implantable trial neurostimulation device of relatively small size and smooth shape, which can be easily implanted and subsequently explanted, so as to avoid the burdens associated with trial implantation of a full-size chronic neurostimulation device or dual-operation device. It is to these ends that further aspects of the invention are directed.